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NuclearPlantJournal.com Nuclear Plant Journal, May-June 2014
Multiple Defense...
while the safe shutdown earthquake
(SSE) adopted in the design is 0.3g,
which leaves a big safety margin.
Safety features:
The AP1000 nuclear power plant,
designed by Westinghouse, is a two-loop
pressurized water reactor (PWR) that
uses a simplified, innovative and effective
approach to safety. With a gross power
rating of 3,415 megawatt thermal (MWt)
and a nominal net electrical output of
1,250 MWe), the AP1000 reactor, with a
157-fuel-assembly core, is ideal for new
baseload generation.
The AP1000 PWR is based on a
simple concept: in the event of a design-
basis accident, such as a main coolant-
pipe break, the plant is designed to achieve
and maintain safe shutdown condition
without operator action, and without the
need for AC power or pumps. Rather than
relying on active components, such as
diesel generators and pumps, the AP1000
plant relies on natural forces - gravity,
natural circulation and compressed gases
- to keep the core and the containment
from overheating.
The AP1000 PWR provides multiple
levels of defense for accident mitigation
(defense-in-depth),
resulting
in
extremely low core-damage probabilities
while minimizing the occurrences of
containment flooding, pressurization and
heat-up. Defense-in-depth is integral to
theAP1000 plant design, with a multitude
of individual plant features including the
selection of appropriate materials; quality
assurance during design and construction;
well-trained operators; and an advanced
control system and plant design that
provide substantial margins for plant
operation before approaching safety
limits. The AP1000 PWR is also the only
Generation III+ reactor to receive Design
Certification from the U.S. Nuclear
Regulatory Commission (NRC).
Based on nearly 20 years of research
and development, the AP1000 plant
builds and improves upon the established
technology of major components used in
current Westinghouse-designed plants.
Components such as steam generators,
digital instrumentation and controls,
fuel, pressurizers and reactor vessels are
currently in use around the world and
have years of proven, reliable operating
experience.
Environment protection
After the completion of Sanmen
Phase I NPP, compared with ultra-
supercritical coal-fired units of the same
capability, the two units may help reduce
transportation of five million tons of high-
quality coal, emission of 11,490 tons of
sulfur dioxide, 19,088 tons of nitrogen
oxide and 1,345 tons of smoke and dust.
Contact: Jackie Smith, Westinghouse
Electric Company, 1000 Westinghouse
Dr., Cranberry Township, Pennsylvania
15632; telephone: (412) 374-3372,
email:
Internal view of Sanmen Unit 1 as of the end of March 2014. Photo courtesy of the Sanmen Nuclear Power Project.
